The RPLS calendar for this month has a photograph of a mini prism in a lovely setting and the caption "6,600-Foot Shot to Control Point.
I checked the specifications of a mini prism. Indeed, the range they claim was 2,000 meters or 6,600 feet, but how do you see something that small from far away?
The longest reading I ever got was over 5,000 feet, but that was using a triple prism (for the size) and a survey road sign behind it to help focus on the target. Even with all that paraphernalia it was very hard to see the target.
Considering the month, is the Photograph meant to fool us?
Naw... But your phone is ringing... Patti Oates, the Realtor is wondering if you'd mind reducing your price... She's crying....
2,000m was the point the old top mounted Topcon DMs would recycle on mid distance shots. Yeah, 6600' was a middling distance back when.
I'm surprised a mini can return a distance that far. I didn't have them during the traverse days, so I never stretched their capabilities.
As far a shooting those distances. We did it all day every day. The farthest I ever did was just short of 30,000' using the HP distance meters. I carried one up a mountain in Nevada to shoot down into a valley before we got the helicopter to ferry us around.
And about being able to see them, pffft, nothing to that. You become trained to do it when you do it all day long.
It gets real fun when you are trying to sight along a hot highway in the summer, and you are splitting the tripod as it jumps back and forth!
I had a Trimble total station for a short time (European model) and it had a "high power" mode on the distance meter. There was a warning on the instrument to not look at it when using that mode. I was shooting across a valley, and you could see the rodman light up red when taking a shot.
With GPS...er.... GNSS, working as well as it does these days I wonder what the circumstance was that called for a 6600 foot EDM shot.
I am with Norman, I dont think I have had a shot over 1,500 feet for a long while.
When we did, a mini-prism didn't always work for us with our old Topcon at 5280+/- feet. I don't remember having trouble getting it sighted in, though. With a robot, it would be interesting to see how well it repeated an angle to a mini-prism 6000 feet away. I would assume it would do just fine, but would want to test it before relying on it.
I’ve set a point a little over 1500’ with a 360 but the radio kept jumping in and out on the robot and I was wondering if I was going to even get it but managed to somehow. 😆
I think those specs are for distance measurements only. The MS60 data sheet states it will shoot a distance over 10000m to a circular prism, but the ATR is limited to 1500m.
I routinely shoot 600m using ATR (reciprocated of course) on GNSS azimuth pairs and the occasional cross tie. That is with a Leica GMP101 mini prism.
As On_Point notes, the radio gets a little wonky at those distances.
